Over the period 2000-2001, 189 private or hospital
laboratories scattered throughout France participated to the laboratory
network RENA-VHC. A total of 759 591 serologies (screening tests and validation
of screening tests) were performed, revealing an increase of 10% between
2000 and 2001. The rate of the amount of tests to validate screening found
positive over the overall amount of tests performed was 1.2% in 2000 and
1.0% in 2001. This suggests that screening covered more people with little
risk of acquiring HCV infection. The persons confirmed HCV positive were
predominantly men (sex ratio 1.5) of which 31% were30 to 39 years of age.

Introduction
Epidemiological indicators on hepatitis C in France indicate that this
disease is a public health issue as regards the number of persons affected
(500 000 to 650 000 persons), long term complications, and not yet fully
controlled transmission modes, in particular in drug users. Following
the identification of the hepatitis C virus in 1989 and the development
of diagnosis tests, the rapid progress of viral, biological, clinical
and epidemiological knowledge has allowed to implement prevention measures,
targeted screening and a more efficient management of patient care.
In 1999, the French health authorities brought together a national programme
to control hepatitis C. In order to contribute to the evaluation of
this programme, the Institut de Veille Sanitaire (INVS, National public
health institute) has developed two national surveillance networks:
surveillance of patients newly managed in specific hospitals and surveillance
of hepatitic C screening through laboratories (RENA-VHC network) in
order to monitor trends and to characterise persons -in terms of age
and sex- screened positive for hepatitis C. This article presents the
results of the first two years of surveillance of RENA-VHC.

MethodsDefinitions
For this surveillance, the following terms were used:Screening test: search for antivirus antibodies specific to hepatitis
C virus (HCV) using ELISA test on a first blood sample.
Validation of screening test: validation of a positive screening
result testing a second blood sample using a test or a technique different
from the ones used for the screening test. The validation test is either
a test for searching anti-HCV antibodies (ELISA or Immunoblot) or a
test for viral RNA search (qualitative PCR).Overall activity: overall number of blood samples taken for screening,
validation of screening and for searching anti-HCV antibodies with no
indication on the prescription context, over a given period of time
(month, quarter or year). The structure of the data collection did not
allow to differentiate those three types of samples. ELISA and Immunoblot
were the techniques used.Validation of screening: overall number of blood samples taken
for a validation of screening whatever the technique used (ELISA, Immunoblot
and PCR), over a given period of time (month, quarter or year).Overall indicator of positivity: rate of the overall number of
anti-HCV antibodies positive tests whatever the prescription motivation
was (screening tests, tests to validate screening , un précised
indication) over the overall activity. Validation indicator of positivity: rate of the number of tests
to validate screening found positive over the overall activity. A person
was defined as confirmed positive for HCV if both tests - screening
and validation of screening - were found positive.

Organisation of the surveillance network
The laboratories invited to participate in RENA-VHC were those that
took part in the national surveillance network for HIV (RENAVI) in 1997
(1). They were spread all over France except for Corsica region. They
could carry out the tests themselves or have them done by other laboratories.
They were either hospital laboratories (157 laboratories contacted),
or private ones (200 laboratories). Their participation in the network
was on a voluntary basis.
All blood samples (except those of children under one year of age) tested
for hepatitis C in a participating laboratory were included in the surveillance,
whatever the test used (ELISA, Immunoblot, qualitative PCR). When a
laboratory did not carry out the tests itself, the results were included
in its surveillance activity. Laboratories ended up with two types of
activity reports:
- a monthly report including: overall activity, validation of screening
activity, overall number of anti-HCV serologies found positive, and
the number of validation of screening tests found positive. These data
were collected depending on the type of test used (ELISA, Immunoblot,
qualitative PCR) and on the persons' gender.
- a monthly report of positive blood samples: for each HCV positive
sample (sample for screening and for validation of screening) the indication
and the type of test used, the person's gender, age or year of birth
were indicated.
These reports were sent to the Institut de Veille Sanitaire on a quarterly
basis. The laboratories' participation to RENA-VHC was defined by sending
at least one quarter's worth of data to the InVS.

ResultsParticipation
The 357 contacted laboratories represented 10.4% of all the laboratories
carrying out or delegating anti-HCV serologies (n=3420) in France. Among
the laboratories contacted, 281 accepted to participate, 17 refused
and 59 never answered. Among the 281 laboratories, 260 (93%) took part
in RENA-VHC for at least one quarter in 2000-2001. They were split between
132 private laboratories (51%) and 128 hospital laboratories (49%).
Among the 260 laboratories, 189 (73% of those that agreed) participated
all along the eight surveillance quarters, and 71 participated irregularly
over one to seven quarters.

Results from laboratories (n=260) that participated for at least
one quarter in RENA-VHC for the period 2000-2001
Those 260 laboratories represented 6.3% of all the laboratories carrying
out or delegating anti-HCV serologies. They were spread all over France
(Figure 1). Their overall activity represented 947 644 samples carried
out to search for anti-HCV antibodies. Their validation of screening
concerned 14361 samples. These laboratories reported 27 862 positive
samples through the monthly reports. Among them, 61% resulted from screening,
35% from validation of screening , and for 4% the indication of the
prescription was not mentioned. Over the two surveillance years, 9637
persons (35%) were confirmed positive for HCV in these laboratories.

Results from laboratories (n=189) that participated continuously
in RENA-VHC during the eight quarters of the 2000-2001 periodGeographical distribution
The 189 laboratories were divided into 91 private laboratories (48%)
and 98 hospital laboratories (52%) and represented 4,6% of all the laboratories
performing or delegating anti-HCV serologies. Overall activity
In total, 361 832 anti-HCV serologies were tested with an ELISA or Immunoblot
in 2000, versus 397 759 in 2001, representing an increase of around
10% (Table 1). For each year, the overall activity concerned a higher
proportion of women (45%) than men (43%; p<0.001), with 12% of tests
for which no information on gender was available.

Overall indicator of positivity
Among the 361 832 serologies carried out in 2000, 14 814 were found
positive for anti-HCV antibodies (ELISA or Immunoblot). The overall
indicator of positivity was therefore 4.0 %. In 2001, it was slightly
lower : 3.8% (15 256 positive serologies on 397 759, p=0.01) (Figure
2).
The overall indicator of positivity was higher each year for men (5.7%
in 2000 and 5.2% in 2001) than for women (3.6% in 2000 and 3.4% in 2001)
(p<0.001), but also higher in 2000 than in 2001 in both men (p<0.001)
and women (p<0.001).

Validation of screening
In 2000, 5363 samples were tested for validation of screening, and 5165
in 2001. Tests to validate screening represented 1.5% of the overall
activity in 2000 and 1.3% in 2001. The proportions of each technique
used were 76% in 2000 and 71% in 2001 for the ELISA or Immunoblot tests
(n=4089 in 2000, n=3650 in 2001) and 24% in 2000 versus 29% in 2001
for qualitative PCR (n=1274 in 2000, n=1515 in 2001).

Validation indicator of positivity
In 2000, validation indicators of positivity were 1.2% (n=4344 tests
to validate screening found positive) versus 1.0% in 2001 (n=3797 tests
to validate screening found positive), (p<0.001) (Figure 2). The
validation indicator of positivity was significantly higher in men (1.7%
in 2000 ; 1.3% in 2001) than in women (1.0% in 2000 ; 0.8% in 2001)
for each year (p<0.001) and higher in 2000 compared to 2001 for each
gender (p<0.001).
Inter-regional distribution of the validation indicator of positivity
in 2000 and 2001 for the 189 laboratories having continuously participated
in the surveillance
Laboratories have been gathered into five inter-regions following the
telephone code for inter-regions. For each year, the validation indicator
of positivity was distributed heterogeneously within the inter-regions.
The highest value was observed in the Ile-de-France region. For each
inter-region, this indicator declined between 2000 and 2001 (p<0.001)
(Table 2).

Distribution by age and sex of HCV positive confirmed persons over
2000-2001
For the 189 laboratories that participated for eight quarters, the total
number of positive samples recorded in the monthly reports was 21 989.
Among those, 7588 (35%) were found positive for the validation test
and represented 7588 HCV positive confirmed persons: 4557 were men,
2972 women (sex-ratio men/women = 1.5 for each year) and 59 were of
unknown gender (anonymous screening). Age characteristics were similar
for both years: the mean age was 48 years (median 43 years) and ranges
from 1 to 97 years. The age was not documented for 93 persons (anonymous
screening and missing data).
Over the two years, the proportion of men confirmed HCV positive was
more important in the age groups 20-49 years compared to women in the
same age groups, and peaked at 31% in the age group 30-39. In groups
aged 50 and over, women confirmed positive were predominant, with in
particular 17% of women in the age group 70-79. However, in the whole
population, the majority of women confirmed positive (22%) was in the
30-39 age group, just like for men (Figure 3).

Discussion - Conclusion
The laboratories' committment during these first years of surveillance
of HCV screening activity was very good over the period 2000-2001 considering
that 260 of the 281 (93%) laboratories that were willing to participate
have sent quarterly results at least once. Among those 260 laboratories,
71 had a disrupted participation that can be explained by: a temporary
disruption of data collection (n=41), a start after the 1st quarter
2000 (n=11), a definitive (n=15) or non documented (n=4) disruption.
Some reasons given were the complexity of data collection, the difficulty
in accessing computer tools that can easily extract the RENA-VHC data
out of all the laboratory data, or an important workload.
For 189 laboratories that participated on a regular basis, the yearly
overall activity slightly increased from 2000 to 2001 with some fluctuations
in the course of the quarters. The validation of screening decreased
slightly during the same period. The stable overall activity observed
during the 1st quarter 2000 could reflect either the basic activity
of RENA-VHC or the setting-up of surveillance. The activity diminishes
during the summer quarter, then increases between the 4th quarter 2000
and the 2nd quarter 2001. This could be linked to the promotion of information
and incitement towards screening by the Ministry of Health for the attention
of health professionals in June and July, then in October 2000. The
decrease observed later corresponds to the summer season. The 4th quarter
increase could be linked to the impact of campaigns intended to the
general public (broadcast campaigns on radios in May, then in October-November
2001, as well as national and regional daily newspapers campaigns in
June 2001).

The overall indicator of positivity tends to diminish slightly between
2000 and 2001 (4.0% in 2000 and 3.8% in 2001). These proportions of
positive samples are similar to the results found in 1997 in a survey
on HCV screening in community practices in the Doubs and Ile de France
regions (2), which revealed a proportion of 5.1% anti-HCV positive serologies.
All these results concerned serologies carried out for both screening
and validation of screening . This can explain that those proportions
are higher than those reported in prevalence studies (3,4).

The proportion of all the positive samples was more important in men
(5.5%) than in women (3.5%). This disparity was also found in the study
on the Ile de France and the Doubs regions (2), with respectively 5.7%
in men and 4.5% in women, as well as in another study performed in 1988
on the free HCV screening programme (5.3% in men and 2.2 % in women,
for a non-incarcerated population) (5).
The validation indicator of positivity was significantly lower in 2001
(1,0%) than in 2000 (1.2%), and can be explained by the increase of
the overall activity, but remained comparable to the 1.2% of HCV confirmed
diagnosis in the prevalence study on persons benefiting from social
security (3).
Each year, variations of the validation indicator of positivity were
observed between inter-regions. For each one of them, the indicator
declined from 2000 to 2001 but remained comparable to the regional seroprevalence
data on HCV in 1994 (3). For instance, the prevalence in the Lorraine
region was 1.1% in 1994 (3) and the validation indicator of positivity
of the region 3 was 1.2% in 2000 and 0.9% in 2001. The indicator is
the highest in the Ile-de-France region (1.7% in 2000 and 1.5% in 2001)
and can be explained by a more important proportion of intravenous drug
users (IDU), for whom the prevalence of HCV infection is the highest
(5). The indicator of positivity was calculated for the PACA region
(Provences-Alpes-Côtes d'Azur) where the population of IDU is
high, and its value was also high in 2000 (1.6%) then declines in 2001
(1.2%). The decreases of those indicators can be explained by the increase
of the overall screening together with the decrease of tests to validate
screening that were found positive. In other words, the screening activity
increases but covers more people with little risk of acquiring the HVC
infection.

Among the 7588 persons confirmed HCV positive, the age distribution
between men and women was very different. The distribution curve peaked
in those aged 30-39 for men (31% of men), then regularly declined for
the oldest age groups. In women, a same peak was observed for those
aged 30-39 years (22% of women), declined in those aged 60-69 years,
then a second peak was observed for those aged 70-79 (17%). The high
proportion of persons confirmed positive observed in those aged 30-49
years (54% for men ; 39% in women) can be explained by an important
proportion of IDUs, either former or current IDUs (5). The high proportion
of women confirmed positive between 60 and over 80 (37%) could be due
to nosocomial infections and a history of blood transfusions before
1990 (6).
The first two years of surveillance of the RENA-VHC network by laboratories
that contributed on a regular basis provided results on the HCV screening
in France that are comparable to previous studies, despite two points:
the fact that RENA-VHC relies on a small number of volunteer laboratories
(4.6% of all the laboratories), and the fact that the regions are unevenly
represented (southern regions being less represented). Although the
data collection is not old enough to highlight clear trends, or to assert
the impact of the screening promoting campaigns organised by the ministry
of health, it appears that the screening activity of the laboratories
that continuously participated in surveillance increased in 2001 of
around 10% compared to 2000. It will be useful to complete these first
results with precisions on the population covered by the participating
laboratories in order to supply refined national and regional evaluations.

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